1. Field of the Invention
The present invention relates to an ink jet printer and, more particularly, to a an ink jet printer which is adapted to reduce peak power consumption in the ink jet printer.
2. Description of the Related Art
Printers are a typical peripheral equipment output devices associated with computer so as to make a printed record of computer information for the user.
Particularly, an ink jet printer is commonly used as a low-priced printer which is excellent in print quality.
An ink jet printer has a CPU (Central Processing Unit) for receiving a signal from a host computer through its printer interface, reading a system program in an EEPROM (electrically erasable programmable read only memory) that stores initial values for operating the printer and the overall system, analyzing the stored values, and outputting control signals according to the content of the program; a ROM (read only memory) for storing a control program and several fonts; a RAM (random access memory) for temporarily storing data during system operation; an ASIC (Application Specific Integrated Circuit) circuit for transmitting data and control signals from the CPU to the various peripheral components; a head driver for controlling the operation of an ink cartridge according to the control signals transmitted from the ASIC circuit; a main motor driver for driving a main motor and for "parling" the ink cartridge; a carriage return motor driver for controlling the operation of a carriage return motor; and a line feed motor driver for controlling the operation of a line feed motor which is a stepping motor for feeding/discharging it paper.
In the operation of the above apparatus, a printing signal from the host computer is supplied through the printer interface thereof, to drive each of the motors according to the control signal of the CPU and thus perform printing. The ink cartridge forms dots by spraying fine ink drops through a plurality of openings in its nozzle.
Ink jet printers of such a construction have been developed for the improvement of a printing rate without any consideration of their peak power capacity. Consequently, the ink jet printers sometimes have to provide a high cost large size power supply section.
Peak power consumption increases usually because the vertical drive motor is driven to transfer the print paper in the vertical direction during a horizontal printing operation or during switching the carriage to the next print line.
That is, the carriage return motor is driven to allow the carriage to return to the start position of the next line after printing a line while the line-feed motor is driven to print the next line.
Such a simultaneous drive operation of the two motors inevitably accompanies increased peak power consumption in the ink jet printer.
Furthermore, it is necessary to design the ink jet printer in accordance with the maximum capacity of the power supply so that disadvantageously the entire system becomes much more expensive and larger in size.
The following patents each disclose features in common with the present invention but do not teach or suggest the specifically recited features of the ink jet printer having reduced peak power consumption of the present invention: U.S. Pat. No. 5,668,581 to Tsuji et al, entitled Ink Jet Printing Apparatus, U.S. Pat. No. 5,351,068 to Moon et al., entitled Ink-Jet Printer Carriage And Paper Motion Overlap Method And Apparatus, U.S. Pat. No. 4,990,930 to Ludden et al., entitled High Speed Thermal Printing Apparatus, and U.S. Pat. No. 5,349,905 to Taylor et al., entitled Method And Apparatus For Controlling Peak Power Requirements Of A Printer.